Various techniques and materials exist for stimulating bone growth, necessitated by trauma, disease, or surgery. Examples of such materials and techniques may be found in Bourne, Biochemistry and Physiology of Bone (Academic Press).
An example of a surgical procedure which creates a need for post operative bone regrowth is cholesteatoma treatment. A cholesteatoma is a cyst or cystlike tumor affecting the middle ear or the bone of the mastoid. The condition leads to erosion of bone, including the ear ossicles (the tiny bones of the middle ear). Surgical treatment of cholesteatoma is problematic as it leaves an open hole in the auditory canal due to the removal of the rear auditory canal wall. This causes problems with the postoperative care of the mastoid cavity. The epithelium which coats the mastoid cavity lacks the capability to export cutaneous scales and earwax as does the auditory canal epithelium. This leads to a collection in the cavity which can result in damage to the coating with the creation of granulations and secretions. Between 10 and 40% of the patients with mastoid cavities suffer from continual or repetitively recurrent secretions after the operation. The shape and size of the cavity can adversely affect the hearing. The vestibule is more easily irritated by thermal stimuli, so that the patient with an open mastoid cavity must close the ear when swimming.
Following surgery there is the danger of the recurrence of a cholesteatoma either through unremoved squamous epithelium cells or through a renewed collection of auditory canal skin. To permanently correct the problem an osteo-inductive substance should be employed to which the adjacent tissue could be stimulated for the purpose of reossification.
Attempts to avoid or to minimize the surgical cavity causes increased risk of cholesteatoma recurrence or a large surgical expenditure. A lasting obliteration of the surgical cavity with a suitable material could utilize the advantages of the radical operation and avoid its disadvantages at the same time. Accordingly, reconstruction or regrowth of the auditory bones would be most desirable.